1. Field of the Invention
This invention relates to casters for the rolling support of furniture and apparatus and more specifically to glove or ball casters with weight actuated breaking capabilities.
2. Description of the Prior Art
It appears that the industry learned very early that a chamber filled with bearing balls between a caster ball and a hemispherical housing would jam and bind the bearings. Some provided relief paths for recirculation and others supplied retainer cages. It appears from the prior art that the accepted approach to breaking was by allowing the ball structure to retract into the supported member whereby the supported member will contact the floor and act as a brake.
S. Szosiak et al, U.S. Pat. No. 1,186,244 requires internal shifting of the ball bearings to allow the caster ball to contact the friction surface of the ball race. Hence the number of bearings is severely limited. No bearings can be placed around the periphery where the shifting would allow a bearing to contact the ball below the diameter. To do so would lock the caster in the non-rotational position permanently. This patent employs a cage to hold bearing balls in place.
N. A. Rabelos, U.S. Pat. No. 3,096,536 is suitable for very lightweight furniture and light service. However, the ball is allowed to retract into the housing in order that the housing will contact the floor. There is no break adjustment possible and dirt can foul the ball seat while the ball is retracted and the housing lowered to the ground to render the burden stationary.
O. W. Jenkins, U.S. Pat. No. 3,744,083 attempts to provide circulation of small roller balls by means of a relief path allowing the small ball bearings to escape contact with the large caster bearing and return to the backside of the movement to return to rolling service. This is a modification of Smith, U.S. Pat. No. 488,954 issued in 1892 and Lennard, U.S. Pat. No. 491,710 issued in 1893.
Therefore it is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the ball caster art.
Another object of this invention is to provide a caster which minimizes wheel lockup when encountering objects such as grains of sand, glass fragments, etc.
Another object of this invention is to provide a caster capable of providing precision movement on respective traveling surfaces.
Another object of this invention is to provide a caster with automatic means of locking when placed under a specific load.
A further object is to provide a caster with a means of breaking the caster globe through the internal design in contrast to the prior art of lowering the leg-support housing to the floor resulting in contracting and transmitting of foreign matter to the internal caster unit;
It is a still further object of this invention to provide a caster whch moves freely on changes in floor surface such as from terrazo or vinyl floors to soft carpeting.
A further object of this invention is to provide a caster with adjustable-controllable means of breaking the caster depending on the weight of the structure into which it is installed;
It is a further object of this invention to provide a caster with a design that minimizes the possibility of attraction of foreign matter and its entrance into the internal region mechanisms of the caster thereby preventing lockup;
A further object is to provide a caster with means of discharging counteracting static electric generation thereby minimizing attraction of foreign matter;
Another object is to provide a caster with a plurality of load receiving and transmitting bearing balls under minimum friction conditions;
A still further object of this invention is to provide a caster of a simple design series that is feasible and economical as to manufacture and marketing.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.